Switch away from classic (bubbling-only) event handling to simplify management of temporary handlers, and to have the ESC key listener use a priority (capturing) handler, to prevent any other keydown handlers or default actions for the ESC key while the panel is open. This does not change the compatibility test results summarized here: https://fossil-scm.org/forum/forumpost/f425a1756c. (IE8 halts JS processing at JSON.parse in antiRobotDefense, anyway.) Also, for non-compatible browsers, there's a new fallback to transform the hamburger button into a simple (non-scripted) link to the sitemap.
check-in: e3376829 user: florian tags: js-hamburger-menu

Cancel the timer to remove the border of the hamburger menu panel after the closing animation, if the menu is closed and immediately reopened by double-clicking the hamburger button.
check-in: c73deeb6 user: florian tags: js-hamburger-menu